Method of rendering porous metals dense.



UNITED STATES PATENT OFFICE.

CHARLES E. SWETT, OF PROVIDENCE, RHODE ISLAND.

METHOD OF RENDERING POROUS METALS DENSE.

No Drawing.

To all whom it may concern: a

Be it known that I, CHARLES E. SWETT, a citizen of the United States,and resident of Providence, in the county of Providence and State ofRhode Island, have invented new and useful Improvements in Methods ofRendering Porous Metals Dense, of which the following is aspecification.

This invention relates to a new art or method of treating a body or massof porous, spongy or discrete metal to render the same more dense, andconsists in applying to such mass a compound of the metal in a fluidstate, in such manner that said compound of the metal will enter theporosities of the metal mass being treated, after which said metalliccompound is reduced to the metal state in place in the porosities. Thisfilling of the porosities with the metallic compound, and reduction, maybe repeated as many times as necessary 0; desirable according to thedegree of density required, and finally results in a solid, dense andhomogeneous mass of metal which was origi nally porous or spongy.

It happens in the course of the manufacture of articles of silver orother metals, especially when certain processes are used, that the metalbody, or some part thereof, is porous, and therefore not acceptable as amarketable commodity. For example, suppose an article, or anornamentation in relief upon an article, be formed in the desired shapeout of a plastic or fluid mass consisting wholly or chiefly of areducible compound of a metal, such as the bromid, chlorid, iodid,fluorid or nitrate of silver, or of copper, or any of the reduciblesalts of a metal, and the mass or bodyso formed be then reduced tometalby any appropriate method of reduction, it will be found that the massin its reduced state will be more or less porous or spongy.

To render such mass or body of porous metal more dense and solid is thechief object of the present invention. This is accomplished by applyingto the mass or body of porous metal a compound of like metal in a fluidstate, and thereafter reducing the fluid metallic compound to metal inplace within the porosities. The porosities of the metal mass willabsorb or imbibe the metallic compound, which has been rendered fluid bysolution in an appropriate solvent or by heat. The reduction of thecompound of the metal within the porosities may be Specification ofLetters Patent.

Application filed May 12, 1908.

Patented Mar. 14, 1911.

Serial No. 432,515.

effected by any means appropriate to the particular material being used.After one such treatment of filling the porosities and reducing asaforesaid, the object will probably still be somewhat porous, and Ithere- 'silver chlorid, by washing or immersing the porous silver bodyin said fluid compound of silver. The fluid compound is absorbed by andsoaks into the porosities, assisted by capillary attraction. I thenreduce the compound to metal in place in the pores, by any well knownand appropriate method of reduction. If silver nitrate in solution hasbeen used, the reduction may be accomplished by heat. If melted silverchlorid has been used the reduction may be accomplished by electrolyticreduction, or by chemical reduction, in any manner well known to thoseskilled in the art. Should greater density be required than results fromone application and reduction of the fluid compound, the treatment maybe repeated until the pores are for all practical purposes filled.

While the foregoing exemplification of the invention is suflicientlycharacteristic admirably to illustrate the nature and principle of theinvention, it will be understood that the invention is by no meanslimited to the manufacture or ornamentation of silverware, nor to anyspecific use, but is applicable to the treatment of porous metalsgenerally, to render the same more dense, and such general applicationis contemplated by the claims.

I claim:

1. The method of treating a mass of porous or spongy metal to render thesame more dense, which consists in filling the pores of said mass with areducible comrous orspongy metal to render the same the same in thepores, until 'the mass so more dense, which I consists in filling thetreated attains the desired density. 10 pores of said mass with areducible c0m- Signed by me at Providence this 6th day pound of themetal in a fluid state,:an 'l of May, 1908. I

v thereafter reducing said compound to metal CHARLES E. SWETT.

' insuid pores, and thereafter repeating the Vitn'esses:

filling of the residual pores with a reduei- EM E'r'r GINLEY,

I ble compound of the metal, and reducing WASHINGTON R. PRESCOTT.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents,

Washington, I). C.

